30th t/a

iTrader: (51)

Im getting a bad misfire at low rpm's and it idles really low too. I took it down the road and above 2500 or 3000 the car just springs to life and runs awesome but below 2500 or 3000 the car sputters and misses. and this is with new plugs and wires? any ideas?? I dont have a scanner so I dont know any codes.

thanks

MikeD101898

iTrader: (5)

I would say plugs, but take it somewhere that can hook it up and tell you exactly what it is.

30th t/a

iTrader: (51)

I doubt its the plugs. this is the 2nd set and they are new. Also being that it misfires below 3000 and all of a sudden roars to life above 3000 tells me its something other than plugs.

2000Z28M6

iTrader: (13)

The obvious things get you sometimes. Tonight when you have a chance pop your hood, make sure no light is hitting the engine and CHECK for arching of any plug wires.

Before then make sure no plug wires are touching the LTs, Believe it or not this will kill your performance.

30th t/a

iTrader: (51)

I just checked the spark plug wires and they are fine. They were not touching the headers at all.

2000Z28M6

iTrader: (13)

Just in case. Whens the last time you swapped the fuel filter?
Next of course is how good are your 02s?
Any Vacuum leaks?

Other obvious question. Did you gap the spark plugs?

30th t/a

iTrader: (51)

fuel filter, its been a couple years. The guy I bought the motor & PCM from ran NGK TR6 and left them gapped right from the box, Although I have try them gapped and that didnt make a difference either. The motor & PCM has a open loop tune so the O2's should matter, I think.

what pisses me off is 2 days ago the car ran totally fine. I put new transmission fliud in the car and the next thing I know it idles like ****. I put new plugs in it and it still idled like **** then I took it for a ride and it was misfiring & sputtering down my road and when I got on the main road, the car just came to life after 3000 or so and ran awesome and when I got under 3000 it started acting up again.

2000Z28M6

iTrader: (13)

In case this is a combination of things I would clear all codes. THis means resetting the PCM and re scanning a few more times to see if any other codes come up. Typically a misfire code is set in motion by something else. Compare your results and keep snooping until you find it.

nofearracing28

iTrader: (7)

I had the same problem with my trans am. Found the code for which cylinder was misfiring and then pulled the plug and wire. Found the porcelin(sp?) was cracked on the plug. Put a new one in it and ran like a champ.

30th t/a

iTrader: (51)

Ok I hooked a spark tester up to the car and it showed Im getting spark so I guess my coils & wires are good.
Then I hooked a scanner up to the car and Im getting a P0102 (pd) mass air sensor or a (VAF) volume Air Flow sensor code, so I disconnected the MAF and that didnt change anything.
I also got a circuit low input code too.


UPDATE:

So I took the the MAF completly off the car and it didnt change a DAMN thing. The car idled the exact same as it did when I have the MAF hooked up. Is this telling me my MAF went to ****??

UPDATE AGAIN

I installed my stock 75mm MAF and of course that DIDNT change a thing. bitch!

Doc

iTrader: (9)

Hey man, just trying to get an idea of what exactly is going on... So you bought this setup (motor and pcm) from somebody and it worked good for a while and now it is performing like ***? And all you have for DTCs is a MAF code? Can you give us more background on the setup...Like what method/software package was used to tune it? Speed Density or Closed Loop fueling? It seems as though if the setup was properly tuned in SD to begin with then if you unplugged the MAF it would/should run fine without it. Lot's of gaps, fill us in and you'll get the help you need.

30th t/a

iTrader: (51)

problem fixed! I did some research using the SEARCH BUTTON and found out people were having the exact problem I was and it turned out to be a engine control fuse. I replaced it and the car runs sweet.

2000Z28M6

iTrader: (13)

where is this fuse? I'm curious.
Pic?

Under hood or interior?

30th t/a

iTrader: (51)

under the hood on the driver side. Theres 2 fuse boxes. Its the box directly behind the head light and the the fuse says "ENG SEN" and its a 20 amp.